Elaine KlapatchNavy’s future: Electric guns, lasers, water as fuelverified_publisherCNNCNN — Imagine ships that fire missiles at seven times the speed of sound without using explosives, or that use lasers to destroy threats at the cost of about a dollar a shot, and vessels making fuel from the very seawater in which they’re floating. That’s the glimpse of the high-tech future the U.S. …